• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.489-490
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• 2010

A novel soft-switching two-switch flyback converter is proposed in this paper. This converter is composed of two active power switches, a flyback transformer, and two passive regenerative clamping circuits.The proposed converter has the advantages of a low cost circuit configuration, a simple control scheme, a high efficiency, and a wide operating range. The circuit topology and experimental results of the new flyback converter are presented.

• Journal of Power Electronics
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• v.3 no.4
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• pp.249-258
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• 2003

This paper presents a high-efficient and cost effective three-phase AC/DC-DC/AC power conversion system with a single two-switch type active Auxiliary Resonant DC Link (ARDCL) snubber circuit, which can minimize the total power dissipation. The active ARDCL snubber circuit is proposed in this paper and its unique features are described. Its operation principle in steady-state is discussed for the three phase AC/DC-DC/AC converter, which is composed of PWM rectifier as power factor correction (PFC) converter, sinewave PWM inverter. In the presented power converter system not only three-phase AC/DC PWM rectifier but also three-phase DC/AC inverter can achieve the stable ZVS commutation for all the power semiconductor devices. It is proved that the proposed three-phase AC/DC-DC/AC converter system is more effective and acceptable than the previous from the cost viewpoint and high efficient consideration. In addition, the proposed two-switch type active auxiliary ARDCL snubber circuit can reduce the peak value of the resonant inductor injection current in order to maximize total system actual efficiency by using the improved DSP based control scheme. Moreover the proposed active auxiliary two-switch ARDCL snubber circuit has the merit so that there is no need to use any sensing devices to detect the voltage and current in the ARDCL sunbber circuit for realizing soft-switching operation. This three-phase AC/DC-DC/AC converter system developed for UPS can achieve the 1.8% higher efficiency and 20dB lower conduction noise than those of the conventional three-phase hard-switching PWM AC/DC-DC/AC converter system. It is proved that actual efficiency of the proposed three-phase AC/DC-DC/AC converter system operating under a condition of soft switching is 88.7% under 10kw output power.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.869-872
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• 2005

In this paper we present a switch wrapper for an AMBA AXI, which is an efficient on-chip-network interface compared to bus-based interfaces in a multiprocessor SoC. The AXI uses an idea of NoC to provide the increasing demands on communication bandwidth within a single chip. A switch wrapper for AXI is located between a interconnection network and two IPs connecting them together. It carries out a mode of routing to interconnection network and executes protocol conversions to provide compatibility in IP reuse. A switch wrapper consists of a direct router, AHB-AXI converters, interface modules and a controller modules. We propose the design of a all-in-one type switch wrapper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.1
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• pp.162-172
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• 1997

In this paper, we investigated the performance of a binary feedback switch algorithm for the ABR(Available Bit Rate) service in ATM networks. A binary feedback switch is also called EFCI(Explicit Forward Congestion Indication) switch and can be classificed into input cell processing(IP) scheme according to processing methods for the EFCI bit in data-cell header. We proposed two implementation methods for the binary feedback switch according to EFCI-bit processing schemes, and analyzed the ACR(Allowed Cell Rate) of source and the queue length of switch for each scheme in steady state. In addition, we derived the upper and lower bounds for maximum and minimum queue lengths, respectively, and investigated the impact of ABR parameters on the queue length.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2464-2466
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• 1998

A switch is a component with two or more ports that selectively transmits, redirects, or blocks optical power in a fiber transmission line. Our switch uses rotation mechanism using stepping motor, hence the common optical fiber can scan and allign to one of the arrayed N optical fibers to provide optical path by electronic precise control. The developed switch is consisted of switching module and its control module. The performance parameters of a switching loss and a repeatability are considered very important. We performed the study to reduce the switching loss and improve the repeatability of switch. The switch can be widely used as a test instrument of optical device and of optical cable in factory, also of optical cable monitoring systems.

• Electrical & Electronic Materials
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• v.7 no.3
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• pp.213-219
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• 1994

Cu compensated Si doped GaAs (GaAs :Si:Cu has been chosen as the switch material. The GaAs material has been characterized by DLTS(Deep Level Transient Spectroscopy) technique and the obtained data were used in the computer simulation. Simulation studies are performed on several GaAs switch systems, composed of different densities of Cu, to investigate the influence of deep traps in the switch systems. The computed results demonstrates important aspect of the switch, the existence of two stable states and fast optical quenching. An important parameter optimum Cu density for the switch are also determined.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.408-413
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• 2002

We demonstrated a polarization dependent type 2$\times$2 optical switch, using a binary reflection type SLM. Reflection type FLC was used as a half wave retardation plate. Two inputs were controlled by each SLM for the desired output direction. In conclusion, in the "1" state the average optical loss was 6.6 ㏈, and in the "0" state the average optical loss was 14.6 ㏈, and measured the switching speed as 75 $mutextrm{s}$. By using this method, a polarization dependent type 2$\times$2 optical switch can be demonstrated and the possibility of a 4-port WDM optical switch also verified.

• The Journal of Korea Robotics Society
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• v.4 no.2
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• pp.155-162
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• 2009

A main distributing frame(MDF) is an interface unit that is used to connect office equipment cables in a telephone company to subscriber cables. Until now, there is no automated switching system for MDFs in Korea. Manual handling of an MDF has some drawbacks; It is time-consuming, very cumbersome, and expensive. It also makes maintenance hard. An automated main distributing frame system is proposed and commercialized in Japan. In that system, a robot gripper inserts connecting pins into the cross point holes of a matrix board, which reveals several disadvantages in the aspects of space, maintenance, fault tolerance, and economical efficiency. This paper describes a newly developed robotic switch board system for MDFs. In the developed system, switches are placed at the cross point of a matrix board. There is one robot in between two switch units, so one robot deals with two switch units. In the system, positioning the robot, opening and closing switches can be done by using only a pair of motors and a pair of solenoids. The newly developed system is compact in size, reduces cost, and shows high reliability.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.365-373
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• 2015

The performance of 4-switch 3-phase inverter(FSTPI) is mainly affected by the unbalanced voltages between two capacitors which replace two switches of conventional 6-switch 3-phase inverter(SSTPI). This paper proposes a DC offset current injection method to compensate the capacitor voltage unbalance for FSTPI. A simplified SVPWM method which can be applied to FSTPI is also proposed. The validity of the proposed methods is verified by computer simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.338-343
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• 2010

Low cost motor drives are being sought for high volume energy efficient home appliances. Key to the realization of such low cost motor drives is to reduce the power electronic converter in terms of its components, particularly the active devices, finding the motor with least complexity for manufacturing and a controller that could extract the desired performance from the machine and converter combination. These and other factors such as self-starting, speed control over a wide range and most of all the crowning aspect of a four quadrant operation with bare minimum number of controllable switch (or switches) remain as formidable challenges for low cost motor drive realization. In this paper, a four quadrant switched reluctance motor (SRM) drive with only one controllable switch is realized by using a two-phase machine. The theory and operation of the proposed four-quadrant SRM drive with the proposed control algorithm for its realization are described. The motor drive is modeled, simulated and analyzed to verify its feasibility for self-starting, speed control and for four quadrant operation and the simulation results are presented. Experimental results confirm the validity of the proposed control algorithm for four quadrant control of the SRM drive. The focus of the paper is mainly directed toward the control algorithm for realizing the four-quadrant operation of the two-phase SRM drive with a single controllable switch converter.